Standby power, also referred to as vampire power, ghost load, idle current, phantom load, or leaking electricity, refers to the electrical power consumed by electronic appliances while switched off or in a standby mode. A common example of an “electricity vampire” is an AC power adapter or wall wart that has no power-off switch. For example, an AC power adapter for a cellular telephone will continue to supply a charge even if the batteries are fully charged or if the cellular telephone is not plugged in. Other electrical devices consume standby power for functional reasons, which are at times justified (e.g., a temperature sensor on a refrigerator) or unjustified (e.g., displaying a digital clock on a radio when nobody is present). The wasted standby power of household electronic devices is typically very small for any one particular device, but in the aggregate the power consumed by all such devices within a household becomes significant.
According to the United States Department of Energy, “Many appliances continue to draw a small amount of power when they are switched off. These ‘phantom’ loads occur in most appliances that use electricity, such as VCRs, televisions, stereos, computers, and kitchen appliances. In the average home, 75% of the electricity used to power home electronics is consumed while the products are turned off. This can be avoided by unplugging the appliance or using a power strip and using the switch on the power strip to cut all power to the appliance.” US Department of Energy, “Home Office and Home Electronics,” 15 Jan. 2008 available at http://www1.eere.energy.gov/consumer/tips/home_office.html, last accessed on Dec. 3, 2008.